Efficient content delivery over wireless networks using guaranteed prefetching at selected times-of-day

Abstract

A method for content delivery includes defining a guaranteed prefetching mode, in which content is continuously prefetched from a content source to a communication terminal of a user so as to maintain the communication terminal synchronized with the content source. One or more time-of-day intervals, during which the user is expected to access given content, are identified. During the identified time-of-day intervals, the given content is prefetched from the content source to the communication terminal using the guaranteed prefetching mode.

The invention claimed is: 
     
       1. A method for content delivery, comprising:
 selecting a time-of-day interval; 
 during the selected time-of-day interval, prefetching given content from a content source to a communication terminal using a guaranteed prefetching mode, by:
 continuously tracking the given content on the content source, so as to detect changes to the given content as they occur during the selected time-of-day interval; and 
 maintaining the communication terminal continuously synchronized with the content source with respect to the given content, throughout the selected time-of-day interval, notwithstanding the changes that occur during the selected time-of-day interval, by continuously prefetching at least part of the given content from the content source to the communication terminal; and 
 
 outside of the selected time-of-day interval, prefetching the given content from the content source to the communication terminal using a best-effort prefetching mode, by:
 tracking the given content less frequently than the guaranteed prefetching mode. 
 
 
     
     
       2. The method according to  claim 1 , wherein prefetching using the guaranteed prefetching mode comprises prefetching less than a threshold percentage of content items that are detected as changed, and wherein prefetching using the best-effort prefetching mode comprises prefetching more than the threshold percentage of the content items detected as changed. 
     
     
       3. The method according to  claim 1 , wherein tracking the given content comprises continuously crawling the given content on the content source. 
     
     
       4. The method according to  claim 1 , wherein tracking the given content comprises receiving from the content source notifications indicative of the changes. 
     
     
       5. The method according to  claim 1 , wherein selecting the time-of-day interval comprises monitoring a usage pattern of the communication terminal by a software agent installed in the communication terminal, and identifying the time-of-day interval based on the usage pattern. 
     
     
       6. The method according to  claim 1 , wherein selecting the time-of-day interval comprises monitoring a temporal pattern of content changes in the content source, and identifying the time-of-day interval based on the pattern of content changes. 
     
     
       7. The method according to  claim 1 , and comprising deciding to prefetch a content item using the guaranteed prefetching mode in response to an instantaneous feature of the content item. 
     
     
       8. The method according to  claim 1 , wherein prefetching the given content comprises indicating to the communication terminal one or more candidate content items for prefetching, selecting by the communication terminal one or more of the candidate content items, and prefetching the selected content items by the communication terminal. 
     
     
       9. The method according to  claim 1 , wherein prefetching the given content comprises indicating to the communication terminal a first signature of a content item to be prefetched, prefetching the content item by the communication terminal, computing a second signature over the prefetched content item, and caching the content item in the communication terminal only if the first signature matches the second signature. 
     
     
       10. The method according to  claim 1 , and comprising visually marking one or more content items presented to a user of the communication terminal as prefetched. 
     
     
       11. The method according to  claim 1 , wherein selecting the time-of-day interval comprises setting the time-of-day interval to a time period during which a user of the communication terminal is expected to access the given content. 
     
     
       12. A content delivery system, comprising:
 an interface for communicating with a content source and with a communication terminal of a user; and 
 one or more processors, which are configured to:
 select a time-of-day interval; 
 during the selected time-of-day interval, prefetch the given content from the content source to the communication terminal using a guaranteed prefetching mode, by:
 continuously tracking the given content on the content source, so as to detect changes to the given content as they occur during the selected time-of-day interval; and 
 maintaining the communication terminal continuously synchronized with the content source with respect to the given content, throughout the selected time-of-day interval, notwithstanding the changes that occur during the selected time-of-Oday interval, by continuously prefetching at least part of the given content from the content source to the communication terminal; and 
 
 outside of the selected time-of-day interval, prefetching the given content from the content source to the communication terminal using a best-effort prefetching mode, by:
 tracking the given content less frequently than the guaranteed prefetching mode. 
 
 
 
     
     
       13. The system according to  claim 12 , wherein the one or more processors are configured to prefetch less than a threshold percentage of content items that are detected as changed when using the guaranteed prefetching mode, and to prefetch more than the threshold percentage of the content items detected as changed when using the best-effort prefetching mode. 
     
     
       14. The system according to  claim 12 , wherein the one or more processors are configured to detect the changes by continuously crawling the given content on the content source. 
     
     
       15. The system according to  claim 12 , wherein the one or more processors are configured to detect the changes by receiving from the content source notifications indicative of the changes. 
     
     
       16. The system according to  claim 12 , and comprising a software agent that is installed in the communication terminal and is configured to monitor a usage pattern of the communication terminal, wherein the one or more processors are configured to identify the time-of-day interval based on the usage pattern. 
     
     
       17. The system according to  claim 12 , wherein the one or more processors are configured to monitor a temporal pattern of content changes in the content source, and to identify the time-of-day interval based on the pattern of content changes. 
     
     
       18. The system according to  claim 12 , wherein the one or more processors are configured to decide to prefetch a content item using the guaranteed prefetching mode in response to an instantaneous feature of the content item. 
     
     
       19. The system according to  claim 12 , wherein the one or more processors are configured to indicate to the communication terminal one or more candidate content items for prefetching, and comprising a software agent that is installed in the communication terminal and is configured to select one or more of the candidate content items and to prefetch the selected content items. 
     
     
       20. The system according to  claim 12 , wherein the one or more processors are configured to indicate to the communication terminal a first signature of a content item to be prefetched, and comprising a software agent that is installed in the communication terminal and is configured to prefetch the content item, to compute a second signature over the prefetched content item, and to cache the content item only if the first signature matches the second signature. 
     
     
       21. The system according to  claim 12 , and comprising a software agent that is installed in the communication terminal and is configured to visually mark one or more content items presented to a user of the communication terminal as prefetched. 
     
     
       22. The system according to  claim 12 , wherein the one or more processors are configured to set the time-of-day interval to a time period during which a user of the communication terminal is expected to access the given content. 
     
     
       23. A computer software product, the product comprising a tangible non-transitory computer-readable medium in which program instructions are stored, which instructions, when read by one or more processors of a content delivery system that communicates with a content source and a communication terminal of a user, cause the one or more processors to:
 select a time-of-day interval; 
 during the selected time-of-day interval, prefetch the given content from the content source to the communication terminal using a guaranteed prefetching mode, by:
 continuously tracking the given content on the content source, so as to detect changes to the given content as they occur during the selected time-of-day interval; and 
 maintaining the communication terminal continuously synchronized with the content source with respect to the given content, throughout the selected time-of-day interval, notwithstanding the changes that occur during the selected time-of-day interval, by continuously prefetching at least part of the given content from the content source to the communication terminal; and 
 
 outside of the selected time-of-day interval, prefetching the given content from the content source to the communication terminal using a best-effort prefetching mode, by:
 tracking the given content less frequently than the guaranteed prefetching mode.